Birth spacing and autism study took into account other factors

Autism risk may be linked to birth spacing, according to a new study of half a million California kids. Image: Flickr / sunsets_for_you / CC-BY-SA

A new preliminary study released today indicates that closer spacing of births and autism risk may be linked. The link of birth spacing and autism took into account other factors, and still showed surprising results. Siblings born within two years of one another show “significantly higher” risk of developing autism.

Half a million children in California studied for autism

The study published in the journal Pediatrics today looked at 500,000 children in California. The researchers adjusted the numbers of children and families with autism for a wide variety of factors. Age of the parents, health of the family, and severity of the autism all were taken into account. No matter what other factors were included, a sibling born within two years of another is at significant risk of developing some form of autism.

Increasing numbers of closely spaced children

The birth spacing and autism study took into account other factors. The increasing numbers of autism in the last few years could be directly linked to children being born closer together. In 1995, 11 percent of all births were considered “closely spaced.” In 2002, 18 percent of births were closely spaced. The incidence of the number of cases of autism is also rising significantly, with about one in every 91 births in 2009 being a child with an autism-spectrum disorder. Some argue that these increasing numbers are partially because of improved diagnosis procedures.

Asking for more study of birth spacing and autism

Though the study considered half a million children in California and considered other risk factors, the researchers caution against making singular conclusions. Instead, the researchers say that this study shows that more research needs to be done. Older parents are also more likely to have autistic children, though researchers point out that older parents also tend to have closely spaced children. This study comes just weeks after British scientific groups completely discredited the research that linked vaccinations and autism risk.